Let's say you are using the ansible-doc command to display documentation on the firewalld module and module firewalld not found is returned.

[WARNING]: module firewalld not found in:
/usr/local/ansible/collections/ansible_collections/ansible:/usr/local/lib/python3.6/site-
packages/ansible/modules

This implies that a collection that contains the firewalld module is not installed on your control node (your Ansible server). firewalld is in the ansible.posix collection. The ansible-galaxy install collection command can be used to install the collection. In this example, the ansible.posix collection is installed.

~]$ ansible-galaxy collection install ansible.posix
Starting galaxy collection install process
Process install dependency map
Starting collection install process
Installing 'ansible.posix:1.2.0' to '/home/john.doe/.ansible/collections/ansible_collections/ansible/posix'
Downloading https://galaxy.ansible.com/download/ansible-posix-1.2.0.tar.gz to /home/john.doe/.ansible/tmp/ansible-local-15258q2alfwvq/tmpdesamf4k
ansible.posix (1.2.0) was installed successfully